The Round Turn and Two Half Hitches is a hitch used to secure the end of a rope to a fixed object such as a pole, column or post. It's redeeming features, it is easily tied and rarely jams. The chief advantage of this knot is that it won't slip along the object to which it is secured.
To Tie a Round Turn & Two Half Hitches:
Pass the end round the post once.
Pass around a second time.
This takes the strain while you tie the knot.
Go round the standing end to make the first half hitch and pull tight.
Continue round in the same direction to make the second half hitch.